The patch titled
Subject: mm: handle write faults to RO pages under the VMA lock
has been added to the -mm mm-unstable branch. Its filename is
mm-handle-write-faults-to-ro-pages-under-the-vma-lock.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-handle-write-faults-to-ro-pages-under-the-vma-lock.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: handle write faults to RO pages under the VMA lock
Date: Fri, 6 Oct 2023 20:53:18 +0100
I think this is a pretty rare occurrence, but for consistency handle
faults with the VMA lock held the same way that we handle other faults
with the VMA lock held.
Link: https://lkml.kernel.org/r/20231006195318.4087158-7-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
--- a/mm/memory.c~mm-handle-write-faults-to-ro-pages-under-the-vma-lock
+++ a/mm/memory.c
@@ -3304,10 +3304,9 @@ static vm_fault_t wp_pfn_shared(struct v
vm_fault_t ret;
pte_unmap_unlock(vmf->pte, vmf->ptl);
- if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
- vma_end_read(vmf->vma);
- return VM_FAULT_RETRY;
- }
+ ret = vmf_can_call_fault(vmf);
+ if (ret)
+ return ret;
vmf->flags |= FAULT_FLAG_MKWRITE;
ret = vma->vm_ops->pfn_mkwrite(vmf);
@@ -3331,10 +3330,10 @@ static vm_fault_t wp_page_shared(struct
vm_fault_t tmp;
pte_unmap_unlock(vmf->pte, vmf->ptl);
- if (vmf->flags & FAULT_FLAG_VMA_LOCK) {
+ tmp = vmf_can_call_fault(vmf);
+ if (tmp) {
folio_put(folio);
- vma_end_read(vmf->vma);
- return VM_FAULT_RETRY;
+ return tmp;
}
tmp = do_page_mkwrite(vmf, folio);
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-make-lock_folio_maybe_drop_mmap-vma-lock-aware.patch
mm-call-wp_page_copy-under-the-vma-lock.patch
mm-handle-shared-faults-under-the-vma-lock.patch
mm-handle-cow-faults-under-the-vma-lock.patch
mm-handle-read-faults-under-the-vma-lock.patch
mm-handle-write-faults-to-ro-pages-under-the-vma-lock.patch
iomap-hold-state_lock-over-call-to-ifs_set_range_uptodate.patch
iomap-protect-read_bytes_pending-with-the-state_lock.patch
mm-add-folio_end_read.patch
ext4-use-folio_end_read.patch
buffer-use-folio_end_read.patch
iomap-use-folio_end_read.patch
bitops-add-xor_unlock_is_negative_byte.patch
alpha-implement-xor_unlock_is_negative_byte.patch
m68k-implement-xor_unlock_is_negative_byte.patch
mips-implement-xor_unlock_is_negative_byte.patch
powerpc-implement-arch_xor_unlock_is_negative_byte-on-32-bit.patch
riscv-implement-xor_unlock_is_negative_byte.patch
s390-implement-arch_xor_unlock_is_negative_byte.patch
mm-delete-checks-for-xor_unlock_is_negative_byte.patch
mm-add-folio_xor_flags_has_waiters.patch
mm-make-__end_folio_writeback-return-void.patch
mm-use-folio_xor_flags_has_waiters-in-folio_end_writeback.patch
